[Tinyos-help] CC2420 setRetryDelay

[JeongGil Ko (John Ko)]

Robert,

The delay value that you specify using setRetryDelay() starts a timer 
after the first packet transmission attempt is done. So 2) would be the 
case. You can checkout the implementations in 
/tos/chips/cc2420/link/PacketLinkP.nc.

-John

Robert Pulumbarit wrote:
> In TEP 126 
> (http://tinyos.cvs.sourceforge.net/*checkout*/tinyos/tinyos-2.x/doc/html/tep126.html), 
> for the PacketLink layer, there is a command called "setRetryDelay." 
>  It is described as follows:
>
> "The second command, setRetryDelay(..), specifies the amount of delay 
> in milliseconds between each retry."
>
> Is specified delay
>
> 1) the time from the start of one transmission try to the start of the 
> next transmission try?
>
> or
>
> 2) the time from the end of one transmission try to the start of the 
> next transmission try?
>
> In other words, when does the delay start counting?  Does it start at 
> the beginning of the first transmission try or the end of the first 
> transmission try?  I have a transmission that takes a relatively long 
> time to complete, so I would like to know how the setRetryDelay is 
> interpreted so that I don't end up overlapping the first and second 
> transmission (which I assume could happen if the first case above (1) 
> is true and I set the retry delay shorter than the time it takes to 
> transmit one message).
>
> Thank you.
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>
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-- 
JeongGil (John) Ko
Ph.D. Student
Department of Computer Science
Johns Hopkins University
http://cs.jhu.edu/~jgko